Oil-burning boiler fire box with air and steam feeding means



Nov. 27, 1951 F. WETZEL 2, 7

OIL BURNING BOILER FIRE BOX WITH AIR AND STEAM FEEDING MEANS Filed NOV. 7, 1947 2 SHEETSSHEET l Fig.1.

, JNVENTOR. FREDERICK WETZEL ATTORNEY F. WETZEL Nov. 27, 1951 OIL BURNING BOILER FIRE BOX WITH AIR AND STEAM FEEDING MEANS 2 SHEETS-SHEET 2 Filed NOV. 7, 1947 m m m m FREDERICK WE TZEL BY flyv ATTORNEY Patented Nov. 27, 1951 UNITED STAT Es PATENT OFFICE Y OIL-BURNING BOILER FIRE BOX WITH AIR AND STEAM FEEDING MEANS H I Frederickwetzel, lSeaverton, Oreg. I 'ApplicationNove-inberfi, 1947, Serial No. 784,645

fire. Frequently the humidity of theair in the f vicinity of a boiler is depleted by the presence of hygroscopic surfaces and materials such as porous metals, rust, pipe lagging, dust, concrete and others. Likewise the high temperature of air in and about a boiler room tends to reduce-its humidity.

One object of the present invention is to provide for the addition of moisture to the air which supports combustion of the boiler fire. Another object is to add moisture in such a manner and in such locations in the boiler as to beneficially alter the firing and heating characteristics-of the boiler. A still further object of the invention is to provide means for controlling dangerously ex cessive boiler fire such as might becaused'by mishandling of the boiler, through the same system employed for increasing efiiciency of com-" bustion in the boiler. Still further and more specific objects and advantages of the invention are made apparent in the following specification wherein the invention is described in detail by reference to the accompanyingdrawings.

In the drawings:

Fig. 1 is a schematic view in vertical section of-a boiler embodying the present invention;

Fig. 2 is a diagrammatic view of a piping sys tem employed in connection with the present invention;

Fig. 3 is a perspective view'of steam header which forms a part of the present invention; and

Fig. 4 is a perspective View of another header also illustrating a pipe associated therewith'for use in conjunction with the suppression ofexcessive fire in the boiler. T

Referring to Fig. 1 of'the drawings, 'a' typical boiler is shown as comprising a'boiler c'asi'rigilll disposed within which is a fireboxill of'iconventional form to which fuel is supplied as by a fuel nozzle I2. Conventional boiler tubes l3 extending between headers l4 and I5 are supported above the fire box and water is supplied to these tubes from a steam and water drum illustrated at 1512.

Superheater tubes I6 are associated with a superheated steam manifold or header I! from 2Clai1 ns. (01. 158-4) 2 which steam is drawn for use in the engine an other parts of the ship. At its uppermost end the boiler casing has an uptake portion I8 for communication with a stack (not shown) and an :economizer unit comprising a set of tubes [9 is disposed within this uptake. In some boilers an air preheater would occupy the same position as the economizer here shown. In operation feed water is directed to the boiler through the economizer tubes I9 50 that it becomes preheated before it enters the drum l5a and passes therefrom into the main boiler tube system.

Air is supplied to support combustion of the oil emitted by the fuel nozzle 12 through an air duct disposed at the back of the fire box and beneath the fire box. Fresh air enters an-opening 20'at the upper back portion of the boiler casing and passes downwardly as indicated by the arrows in Fig. 1 to flow behind and beneath the fire box where it is preheated and then to flow upwardly forwardly of the fire box and enter' through a port 21 through which the fuel oil is sprayed by the nozzle l2.

Because of conditions usually existing in the P vicinity of an operating boiler the humidity of the'air entering through the air duct is below normal and insuflicient to support perfect combustion of the fuel burned in the fire box. Therefore, according to the present invention a steam header 23 is disposed in the air duct beneath the floor of the fire box. This steam header, shown in detail in Fig. 3, is provided with a plurality of nozzles 24 directed forwardly of the boiler or in the direction of the fiow of air through the air j-dl10'b. The header 23 is connected as by a'pipe 25; as shown in Fig. 2, with a drain at the lower end of the superheated steam header I! and flow through the pipe 25 is under control of a valve 21. Consequently superheated steam may be directed to the header 23 and projected through the nozzles thereof in the direction of the air flow and added to the air which supports combustion of the fuel within the fire box II." This creates more complete combustion of the fuel .in'the fire box than wouldotherwisebe obtainable.

A second steam header shown at 28 is disposed in the uptake of the boiler casing just below the nected as by a pipe 33 with a fitting 26 on the' superheated steam header l1 and the flow of steam to the header 28 is under control of a valve 34. By projecting superheated steam through the header 28 and upwardly through the uptake of the boiler any obstruction caused by the economizer tubes in the uptake is overcome by the increased upward fluid flow through the throat. Thus the fire in the fire box I I tends to be drawn upwardly through the main bank of boiler tubes 13 and superheater tubes I6 so that the efliciency of the boiler is increased and any tendency of the fire to strike the back wall of the fire box and swirl therein is minimized. Furthermore, the

superheated steam projected upwardly by the nozzles of the steam header 28 directly contacts the tubes [9 of the economizer and'heat isadded to the normal heat of the gases passing upwardly through the uptake of the boiler to preheat the water which is being added to the boiler tube system.

.Disposed directlybeneath the steam header 28 is a pipe 35, also shown in Fig. 4 as having perforations 36 formed in its lower side to projectsteam downwardly toward the fire box of the boiler. The pipe 35, as illustrated in Fig. 2, is connected as by a pipe 31 with the superheated steam chamber H and is undercontrol of a valve illustrated at 38.

.In operation of the boiler normally "both the steam headers 23 and 28 will be in open communication with the superheated steam chamber I"! and superheated steam will be projected through the nozzles of these headers. The header 23 in addition to adding the moisture of the steam to the air passing through the duct and entering the fire boxes for combustion therein will add to the velocity'of this air .and thereby minimize the requirements of blowers sometimes employed .for this purpose. Furthermore, by adding moisture to the products of combustion within the .fire box it will minimize the carbon accumulation therein and generally improve the quality of combustion. upwardly from the header 28 will increase the draft through the boiler and cause the greater heat of combustion in the firebox to be drawn directly upwardly from the ,fire .box through the bank of boiler tubes l3, thus also increasing the efficiency of the boiler. In the event that excessive or destructive fire should occur in the boiler, steam may be admitted thereto through the steam pipe 35 and directly downwardly over the boiler tubes. The admission of steam in this manner can be effected by opening the normally closed valve .38 and will preferably be accompanied by closing the valve 34 to the header .28 However the steam should preferably .still flow through the header 23 and may even beincreased through this header. Thus in the event of fire, superheated steam will be directed downwardly toward the fire-box, as well as upwardly and will tend to blanket and confine the fire therein to prevent the disastrous results .of excessive fire in the boiler.

The invention herein described is also particularly useful in controlling variationsin humidity which occur because of a ship travelling through different climates in differentpa'rts of the world. By adding humidity to the boiler fire in dry The steam projecting 4 climates the quality of combustion is maintained high and thus the accumulation of carbon on the boiler tubes and in other parts of the boiler is prevented. The superior combustion provided by proper regulation of humidity tends to destroy accumulated carbons and also tends to reduce any carbon within the boiler to a powdery form that does not readily adhere to boiler tubes and is'held in suspended form where it may readily be carried away by the boiler draft.

The reference in the claims to a large volume low velocity air duct relates to the type of air conduit conventional in various makes of boilers which duct is as wide or almost so as the fire box itself, and into which air flows by a natural draft or'by low pressure blowers as distinguished from high pressure air equipment where air is forcibly projected through a pipe. Such boilers are sometimes referred to in the trade as the double front or double cased forced draft type.

v I claim:

1. In a steam boiler comprising a fire box, an oil burner operatively associated with said fire box :for directing fuel thereinto,.an 1an air duct communicating with said fire box adjacent said burner for directing a large volume of relatively low velocity air into the fire box in the vicinity of the burner, a steam pipe extending through the air duct in a direction transverse to the how of air therethrough, a plurality of, nozzles pro! jecting from said pipe and extending generally in the direction of said fiow, and means for introducing superheated steam to said pipe.

.2. .Inasteam boiler comprising a fire box, an

oil burner operatively associated with said fire box for directing fuel thereinto, and an air duct communicating with said .fire box adjacent .said burner for directing a large volume of relatively low-velocity air into the fire box in the vicinityof the burner, a steam pipe extending through the air duct in a direction transverse to the flow of air therethrough, a plurality of nozzles :projecting from said pipe and extending at diverging angles but-all generally in the direction of said flow whereby steam issuing from the nozzles will tend to spread throughout substantially the entire cross sectional area of the duct, and means for introducing superheated steam to said pipe.

FREDERICK WETZEL.

REFERENCES CITED The following references are ofrecord in the file of this patent:

UNITED STATES PATENTS Skinner June .26, 1923 

